628 Emerson: BLACKENING OF BAPTISIA TINCTORIA 
week; then the solutions had all become a rich, red, clear sherry 
color, that with distilled water also having a reddish tinge. 
4. One drop of twenty per cent. ferric chloride turned a solu- 
tion of freshly chopped leaves in water a deep black, showing the 
presence of tannin, but none could be detected in the alcoholic 
extracts. 
5. The various extracts seemed to be quite neutral, that is, they 
produced no change in either blue or pink litmus paper, even when 
kept some days so that there was a decided musty or cider smell. 
A few drops of chloroform do not affect the action of the enzymes 
and keep the solutions from growing musty. 
In the field those branches which had turned black were in 
general injured in some way, by being stepped on, blown over or 
sometimes some insect eggs were found in the hollow stems of 
older branches. These are some suggestions as to the possible 
cause for the starting of the action of the enzymes. 
In the plants which are described in Woods’ interesting paper 
he enzymes show much greater activity in or near the cells which 
are injured in a leaf than in the normal green cells. He suggests 
that the insects which cause punctures may “inject substances 
possibly related to saliva into the wounds which they produce, 
and it may be the irration caused by these substances which 
is responsible for the increase of oxidase and peroxidase.’’ He 
also states that these enzymes rapidly destroy chlorophyl and that 
‘under certain conditions not yet well understood” they “ either 
become active or else are produced in abnormally large quantities, 
causing variegations and various diseases.”’ * 
‘The oxidizing enzymes are evidently contained in the plas- 
matic living part of the cell, and not in the cell sap which 
fills the vacuoles. On the other hand, the matters easily oxidized 
by them and representing products of metabolism or by-products 
of certain synthetical operations are mostly contained in the cell 
sap. These matters, often of a chromogenic character, are, of 
course, produced in the plasmatic parts, but secreted rapidly into 
the cell sap. When the cells die the soluble substances locally 
separated in the cytoplasm and the cell sap intimately mix, since 
the coagulating protoplasm, becoming easily permeable, can no 
* Woods Fete peer a 
Tl: tees 
